Question

y=f(x)=-5^x
find f(x) when x=3

Answer 1

\[\Large\rm f(\color{orangered}{x})=-5^{(\color{orangered}{x})}\]\[\Large\rm f(\color{orangered}{3})=-5^{(\color{orangered}{3})}\]

Answer 2

The important thing to realize here (actually it doesn't affect this problem though) is that you're not applying the power to the negative sign (since it isn't in brackets).

Answer 3

\[\Large\rm f(\color{orangered}{3})=-5\cdot5\cdot5\]